Fluorine-containing compounds having a fluorine atom in the molecule are excellent in thermal stability and chemical stability, and those that are partially modified with other functional groups are used as additives for lubricating oil, etc. Among such fluorine-containing compounds, those whose end group is modified with a compound having a nitrogen atom have moderate coordination ability, because they contain a nitrogen atom that has a conjugated electron pairs in the molecular structure. Therefore, they are excellent in absorption to metal surfaces, and are considered to exhibit excellent performance as lubricating oil additives.
As an example of such additives, Patent Document 1 proposes a lubricant for magnetic disks, the lubricant comprising a stabilized compound having repeating units —(CF2)nO— and an end group —CH2NRR′. However, the production of the compound necessitates methanesulfonyl chloride, which is expensive, and requires specific reaction procedures (e.g., reactions under anhydrous conditions). For these reasons, it is difficult to scale-up the production.
Moreover, Patent Document 2 proposes a fluorine-containing compound having a pyridine ring. The production method thereof is very simple, that is, a pyridine derivative and a fluorine-containing alcohol are only mixed in the presence of a phase-transfer catalyst. However, to obtain the fluorine-containing alcohol used in the reaction, esterification reaction of the corresponding acid fluoride and reduction reaction are generally required, as described in Patent Document 3. This suggests that the method includes many steps.
Furthermore, Patent Document 4 discloses a method for producing a fluorine-containing polyether carboxylic acid amide by reacting a fluorine-containing polyether carboxylic acid chloride and an aromatic amine. For the carboxylic acid chloride used in this reaction, it is necessary to convert the corresponding carboxylic acid fluoride to a carboxylic acid by hydrolysis, and then reconvert the carboxylic acid to a carboxylic acid chloride using thionyl chloride or phosphorus pentachloride. Such many reaction steps are disadvantageous in the actual production. In addition, since the reaction temperature is maintained at 5° C. or less, the reaction conversion decreases, and the yield is as low as about 75 to 85%.